Method for reproducibly preparing a low-melting high-carbon yield precursor

Abstract

The present invention is directed to a method for preparing a reproducible synthetic carbon precursor by the autoclave polymerization of indene (C9H8) at a temperature in the range of 470 DEG -485 DEG C, and at a pressure in the range of about 1000 to about 4300 psi. Volatiles in the resulting liquid indene polymer are removed by vacuum outgassing to form a solid carbon precursor characterized by having a relatively low melting temperature, high-carbon yield, and high reproducibility which provide for the fabrication of carbon and graphite composites having strict requirements for reproducible properties.

What is claimed is: 
     
       1. A method for preparing a thermoplastic carbon precursor comprising the steps of confining indene in an autoclave containing an inert atmosphere, heating the indene to a tempertaure in the range of 470°-485° C. at a pressure in the range of about 1000 to 4300 psi for a duration sufficient to convert the indene to a liquid polymer, reducing the temperature and pressure to ambient conditions, and thereafter vacuum outgassing volatiles from the liquid polymer to provide a solid polymer having a melting temperature in the range of about 40°-105° C., a viscosity in the range of about 880-26,800 centipoises, and a carbon yield in the range of about 52-66 weight percent. 
     
     
       2. The method according to claim 1, wherein said duration sufficient to convert the indene to a liquid polymer is in the range of 1 to 3 hours, and wherein the outgassing step is achieved at a temperature of 100° C. for a duration of 20 to 24 hours. 
     
     
       3. A thermoplastic carbonizable material comprising polymerized indene derived from heating indene in an inert atmosphere at a temperature in the range of 470°-485° C. and at a pressure in the range of about 1000 to 4300 psi and outgassing the resulting liquid polymer for converting the indene to a solid thermoplastic polymer, said polymer being further characterized by possessing a melting temperature in the range of 40° to 105° C. and a carbon yield in the range of about 52 to 66 weight percent.